MRC RT01
Does escalating conformal prostate RT from 64 Gy to 74 Gy improve biochemical control?
Absolute Effect
10-year OS was identical at 71% in both groups (HR 0.99, 95% CI 0.77–1.28; P=.96).
Biochemical progression was reduced: 43% of the control group versus 57% of the escalated group remained free of progression at 10 years.
Treatment burden and toxicity
Dose escalation increased late bowel toxicity. Grade ≥2 late bowel toxicity was more frequent; rectal bleeding, diarrhoea and proctitis all increased with escalation.
Quality of life: Patient-reported bowel and sexual function worsened during treatment; overall late severe bowel toxicity remained at clinically acceptable absolute levels.
Subgroups / clinically important modifiers
The trial supports biochemical-control improvement across the enrolled localized-risk population, but no OS advantage was demonstrated.
Limitations and maturity
The control dose is obsolete by current standards, and modern IMRT/image guidance may reduce the toxicity penalty.
Clinical interpretation
RT01 is the key randomized dose-escalation step showing that better biochemical control does not automatically translate into longer survival; toxicity must be included in the absolute-effect calculation.